如何在结束循环之前查看发生器的打印输出? [英] How to see print output from generator before ending the cycle?

问题描述

我正在尝试在包含大量数据的生成器中打印调试信息.但是，只有在生成器完成后，我才能看到结果.

I'm trying to print debug information inside a generator working with big list of data. But, I can see the result only when the generator finishes.

我正在使用python 3，我的代码如下:

I am using python 3 and my code is as follows:

def generator():
    while 1:
        print ('.', end='')
        time.sleep(1)
        yield 1

for a in generator():
    print ('|', end='')

结果:

^C.|.|.|.|.|

等效的PHP7代码按预期工作:

Equivalent PHP7 code works as expected:

function generator()
{
    while (1) {
        echo '.';
        sleep(1);
        yield 1;
    }
}

foreach (generator() as $item) {
    echo '|';
}

结果:

.|.|.|.|.|^C

如何在生成器周期的每次迭代中实时打印调试信息?

How to print debug information in realtime for each iteration of the generator's cycle?

推荐答案

TL; DR:

我认为您对此问题也有类似的问题:

I believe that you have a similar issue to that question: Print statements not working when serve_forever() is called? (although by the title is not apparent...)

尝试冲洗您的照片:

print ('.', end='', flush=True)

print ('|', end='', flush=True)

---

冲洗

flush()方法刷新内部缓冲区，例如 stdio的刷新.对于某些类似文件的对象，这可能是空话.

The method flush() flushes the internal buffer, like stdio's fflush. This may be a no-op on some file-like objects.

它强制将print()功能打印到该点为止的任何内容缓存到计算机的stdout.

It forces the print() function to print whatever have been buffered up to that point to the stdout of your machine.

这篇关于如何在结束循环之前查看发生器的打印输出?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！